Dangerous Space
This is the text version of the interactive 3D documentary. 한국어
Danger ranking › Nearby stars
Betelgeuse
Nearby stars #3 · It will explode as a supernova one day — but at a safe distance from Earth
View in 3D- Name
- Betelgeuse (α Orionis)
- Type
- Red supergiant
- Size
- More than about 700 times the Sun’s diameter
- Distance
- about 550 light-years from Earth · light takes 550 years (The estimate varies a lot (roughly 500–650 light-years))
The story in 3 scenes
Orion’s red shoulder
It is the red star on the upper-left shoulder of Orion in the winter sky. It has swollen so much that, placed where the Sun is, it would swallow everything out past the asteroid belt. It is in the last stage of its life.
Why?Stars much heavier than the Sun burn through the fuel in their core quickly. At the end, the core collapses and the star explodes as a supernova.
What nextNo one knows exactly when. Many estimates say within the next 100,000 years.
See this scene in 3D →The Great Dimming
From late 2019 to early 2020, Betelgeuse faded to roughly a third of its usual brightness. People started asking whether it was about to explode.
Why?Observations from the Hubble Space Telescope and the European Southern Observatory showed that gas thrown off by the star cooled into a cloud of dust that blocked its light.
What nextIts brightness came back within a few months. It wasn’t a sign of an explosion, but it was a rare close look at an old star losing material.
See this scene in 3D →Far enough to be safe
Scientists think a supernova would need to be within roughly 50 light-years to badly damage Earth’s ozone layer. Betelgeuse is more than ten times farther away than that.
Why?A supernova’s X-rays and gamma rays weaken with the square of the distance. At about 550 light-years, the amount reaching our atmosphere is far below the danger level.
What nextWhen it explodes, it is expected to be visible in daytime for weeks and to shine about as bright as a half Moon at night. Not a danger — a show.
See this scene in 3D →Sources
Wikipedia: Betelgeuse · ESO: the Great Dimming of Betelgeuse
Impact-threat rankings and probabilities follow NASA/JPL’s Sentry risk table (as of 2026-11-04). The other categories are editorial rankings using the published criteria. Distances to stars can carry large uncertainties.